I am using PPPoE on an Eero Pro 6 to connect to Bell Fibe fiberoptic service in Canada. My Eero Gateway is connected to the Bell Homehub 4000 and I provided Bell's PPPoE credentials in the Eero app.

The PPPoE connection works (as verified by seeing an external IP different from 192.168.*.* in the Eero app), but it is lost every time the service goes down either by losing power or having a fiberoptic outage. When this happens, the Eero acquires a 192.168.*.* IP address from the Bell Homehub meaning that my network is behind two layers of NAT which affects speeds and makes any servers I expose unavailable from outside the network.

Fixing this state always requires reentering the PPPoE password followed by a hard reboot of the Eero gateway.

How can I ensure that the PPPoE connection survives reboots and service outages without falling back to double-NAT every time?